The power of 'click chemistry' has been extended to the world of separation analysis by a team of scientists in China.

Aiwen Lei at Wuhan University and his team have used 'click chemistry' to immobilise different functionalised molecules on silica beads, used as a packing material in high performance liquid chromatography (HPLC) columns. The 'click chemistry' concept was first referred to in 2001 by Barry Sharpless and co-workers and describes highly efficient approaches to joining molecular units together. The technique could lead to improved HPLC separations in many research fields said Lei, who has used a copper-catalysed 'clicking' process between azide-silica beads and functionalized terminal alkynes to make the functionalised packings.

The functionalised silica beads act as the stationary phase in the HPLC column. The team prepared several columns, or 'click columns', using packings functionalised through the click process. An important part of developing the columns, explained Lei, is to find highly selective and effective reactions for immobilisation of the functionalised molecules. One of the columns containing a polar stationary phase was used successfully to separate sugars.

Extending the use of click chemistry in this way may attract the attention of many chemists, said Lei. HPLC is a frequently used tool for separation analysis, he explained, but traditional HPLC cannot resolve problems that exist in the separation of very complex natural products. 'Providing novel HPLC columns with novel separation media is one of the most important approaches to resolve these separation problems,' he said.

James P. Collman of Stanford University in the US said 'It is becoming increasingly clear that the application of "click" chemistry to surface science is becoming significant.'

The team hope they will be able to develop their click columns for the urgent problem of separating the highly complex mixtures of traditional Chinese medicine, said Lei.

Katherine Davies